HI Joey,
On Wed, 11 Dec 2019 at 04:44, Joey Jiao joeyjiaojg@163.com wrote:
Hi Mike, Thanks for you reply, I did notice those snapshots, but don't understand what to provide there. For example I'm not familiar with below ini content if my device is using Cortex-A53 and what the regs for these registers and how to get the kernel_dump.bin.
But I searched kernel documentation which also mentioned to use ptm2human. So let me try that tool at the moment.
BTW, is ETM able to get user space address? I think the OpenCSD perf documented so, but I can only get some kernel address from ptm2human. 0x0000000000000000, 0xffffff9c7d4ff094, 0xffffff9c7d566198, 0xffffff9c7e0f758c,
ETM will trace all address ranges by default. However the range of addresses you see in any output will depend on the size of the sink buffer in use - it is possible that this has wrapped and you are seeing only kernel addresses in the data.
[device] name=cpu_0 class=core type=Cortex-A53
[regs] PC(size:64)=0xFFFFFFC000081000 SP(size:64)=0 SCTLR_EL1=0x1007 CPSR=0x1C5
[dump1] file=kernel_dump.bin address=0xFFFFFFC000081000 length=0x00050000
This is only one of a number of files that make up a snapshot - this describes a CPU and memory images / programs that were present during the trace session. There can be multiple dump sections. In the case of the CPU registers these are not important for trace decode, however in files that describe etm devices the registers are required to ensure correct decode in all circumstances. The format of snapshots is explained in the document OpenCSD/master/decoder/docs/specs/ARM Trace and Debug Snapshot file format 0v2.pdf . The docs/prog_guide/prog_guide_main.md contains an introduction to coresight trace debug. The explains the 3 stages of decode. 1) Trace frames to individual trace streams 2) trace streams to trace packets - these contain atoms and addresses - the level of trace decode provided by ptm2human. 3) trace packets to full trace decode - this stage needs the program images to determine the actual instructions traced.
I would advise reading these two documents along with the ETMv4 specification to understand how coresight trace decode works.
Regards
Mike
At 2019-12-10 19:07:25, "Mike Leach" mike.leach@linaro.org wrote:
Hi Joey,
Please provide more information on the problems you are encountering and any errors you are seeing. Without this I cannot investigate further.
- How are you attempting to use OpenCSD to decode this file? The
trc_pkt_lister test program will provide the same packet decode as PTMtoHuman but does require additional context to ensure that the decode is correct. This involves providing the raw data and certain ETMv4 registers in a "trace snapshot" format. The library comes with examples in this format and a specification for this format in the documentation.
- If you wish to go beyond packet decode then OpenCSD can do that -
but you will need to provide additional program image data - again in the snapshot format described above.
Thanks & Regards
Mike
On Tue, 10 Dec 2019 at 07:55, Joey Jiao joeyjiaojg@163.com wrote:
Hi Mike, I cannot attach the dump into github, so I have to ask here.
OpenCSD cannot decode the etm binary attached, however an opensource ETM decoder https://github.com/hwangcc23/ptm2human can parse.
Can you help understand why?
And is there any bug in OpenCSD?
Thanks
Joey
-- Mike Leach Principal Engineer, ARM Ltd. Manchester Design Centre. UK